DirectionsPreheat the oven to 450º. Melt 2 Tbsp butter. Set aside. Beat the 4 egg yolks with half the superfine sugar. When pale, quickly work in the flour. Beat the 3 egg whites until very stiff and gradually beat in the remaining superfine sugar. Beat the egg whites and melted butter into the egg yolk mixture. Pour the batter into 2 buttered 9 inch cake pans. Bake for about 8 minutes or until a skewer inserted into the center of the cakes comes out clean. Remove the cakes from the oven, unmold and leave to cool. Mix half the rum with the crème de marrons in a warm bowl. Add the remaining butter and the cocoa. Beat well until smooth. Put the chestnut paste into a pastry bag fitted with a plain 1/4" nozzle. Pipe over the sides of an oiled 9" savarin mold in successive rings. Leave in the refrigerator to set. Dissolve the granulated sugar in the water and remaining rum. Bring to a boil and boil for 2 minutes. Moisten the two cake layers with this syrup, and break one layer into pieces. Place the whole cake layer on a flat serving plate. Slide the chestnut case out of the savarin mold and place the case on the cake layer. Fill the chestnut case with alternate layers of broken cake and whipped cream. Place the rest of the whipped cream in a pastry bag fitted with a plain 1/2" nozzle and pipe the cream over the whole cake. Serve at once.